How to setup for easy switching between PLA ABS

[terrypin 3]

I'm returning after a very long gap to my 3D printing with Cura and my Ender 3 V2. But making heavy weather of what I thought a simple task.

 

I've always used PLA. Now I'm trying ABS, but getting in a real mess. Firstly, can someone explain whether this should be set in Cura or on my Ender 3 V2? It seems both are possible, but the Ender 3 V2 itself seemed simple: I just chose the 'Preheat PLA' setting and watched the temps climb from 60 to 70 and 200 to 240, for bed and filament,  respectively. But as soon as I start printing, those temperatures start dropping back to the PLA defaults! Resiult: no ABS gets placed.

 

Am I right that Cura sets this in the Gcode file and that overrules the printer settings? If so, what is the simplest way to set up Cura so that I can simply choose the filament before I create the gCode please?

 

As a separate issue, 70 seems significantly lower than the 90-110 I see recommended on the web? 

 

Terry, UK

Edited yesterday at 03:14 PM by terrypin
typo

[GregValiant 1,366]

Remember that the printer and Cura do not actually know each other.  The only communication is one way and is usually via a gcode file.  Whatever is in the Gcode will override whatever you originally did on the LCD.  You need to set Cura up to print ABS by going through the settings and making sure they are suitable for the material.

 

You are correct that the typical build plate temperature for ABS would be over 100°.  Understand that ABS really requires a "heated build volume" to limit the chances of prints warping and destroying themselves.  Printing ABS gives off noxious fumes and a vent system is advised so the fumes don't build up in an enclosed area.  It isn't something you would want to print in your bedroom on an Ender 3 or an Artillery Sidewinder.

 

M145 sets the material defaults in the printer.

If you were to "print" these three lines (in a gcode file) the material defaults would be changed, and the M500 would save those changes.

M145 S0 H205 B60 F127

M145 S1 H240 B105 F0

M500

You cannot change the material names because they are hardcoded in the firmware.

S0 = "material 1" and is usually PLA

S1 = "material 2" and is usually ABS

H = hot end temperature

B = bed temperature

F = Fan speed in PWM (255 = 100% duty cycle so the 127 indicates 50%)

 

You need to set Cura up for the material you intend to print.  There will be heating commands in the gcode and they will set a new value to whatever pre-condition you did from the LCD.  If you were to set the Feed Rate on the LCD to 125% and then start a print, but you have an M220 S100 in your StartUp Gcode, then when the gcode is printed, the Feed Rate will be set to 100%.  The latest command that the printer/processor sees will be the setting value.

 

 

 

[terrypin 3]

Thanks Greg, very helpful. My focus at the moment is getting my BT Broadband running  (iPad is poor substitute), but asap I will follow up your suggestions. Never written any gCode before, so can I ensure I’ve interpreted this correctly.

 

I will enter those three lines to a text file test.gcode, copy that onto my micro SD card (shared with a lot of files from Cura), insert that into my already running Ender 3 V2,  choose ‘Print’ from its LCD menu, and select test.gcode. How do I proceed to benefit from that, for printing from any of my other gCode files?

 

[GregValiant 1,366]

When you have the "Material Presets" in the printer match what you will enter into Cura, then when the Cura gcode runs it won't actually make changes to the temperatures.  The incoming gcode commands will match your "material presents"for the print and bed temps in Cura.  (Most people start with the fan off regardless of the material type.)

 

When you select a material (for example "Generic ABS") in Cura it should update the Cura settings to what the material has set.

Once you get everything set up in Cura (Layer Height, Line Width, Temperatures, Speeds, Supports, etc.) then click on the "Profile Name" (like "Normal" or whatever you have) and at the bottom of the list of profiles will be "Manage Profiles".  Create a custom profile based on your current settings.  It will be available for you to load and you won't have to make so many changes for each project.

 

Below you can see that I have 4 custom profiles.  All of them started life as "Standard" but each has custom values for a lot of settings.  You can also see that I have a 0.6 nozzle installed.  That tells me that I need to check things like the line width and layer height because depending on the order you make your selections (material first or profile first, etc.) you can get some over-rides in the settings that you may not want.  I consider each Custom Profile to be a  "starting point" and then I customize from that point to create a special set of settings for the particular project I'm working on.  I don't bother to save those special sets.  If I think I might use them again for something else then I will use the "Save Project" command.

 

As I like to say "There ain't no Easy Button in Cura."  It's up to the user to make sure things are correct and that the settings (more than 630 now) will work well together.

 

 

It is important for you "StartUp Gcode" to get the machine ready to print.  If you post what you have as your StartUp we can make some suggestions so that regardless of the material, everything starts smoothly and without wasting time.

You can find the startup gcode under Manage Printers and Machine Settings.

Edited 1 hour ago by GregValiant